MANAGEMENT CONSIDERATIONS

SPECIES: Elymus repens
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Quackgrass provides cover for numerous small rodents, birds, and
waterfowl [30,45].
PALATABILITY :
Many palatable hybrid crosses of quackgrass and other species have been
developed and planted for livestock [2]. Feeding trials in Minnesota
showed that a quackgrass biotype was as palatable as alfalfa (Medicago
spp.) [37]. In cattle grazing trials in Montana, preference was shown
for some clonal lines of a quackgrass-bluebunch wheatgrass
(Pseudoroegneria spicata) cross [46].
The degree of use shown by livestock for quackgrass in five western
states has been rated as follows [14]:
CO MT ND UT WY
cattle good good good good good
sheep fair fair fair good fair
horses good good good good good.
NUTRITIONAL VALUE :
Quackgrass has been rated fair in energy value and poor in protein value
[14]. However, food value studies in Minnesota showed that quackgrass
had as much crude protein as alfalfa during May [37]. These authors
list concentrations of 10 minerals found in quackgrass in Minnesota.
Results of Alaskan studies showed that quackgrass did not contain enough
magnesium required for ruminant digestion nor did it have a high mineral
content. However, digestibility was 64 percent and greater in three
harvest trials [38].
COVER VALUE :
The degree to which quackgrass provides cover for wildlife has been
rated as follows [14]:
MT ND UT
small mammals good fair good
small nongame birds fair good fair
upland game birds good good fair
waterfowl good good fair
VALUE FOR REHABILITATION OF DISTURBED SITES :
Quackgrass has been used to revegetate mine tailings in Nova Scotia
[48]. A quackgrass/Fairway crested wheatgrass hybrid may be useful for
revegetating mine spoils and roadsides [2].
OTHER USES AND VALUES :
NO-ENTRY
OTHER MANAGEMENT CONSIDERATIONS :
Although quackgrass is considered an undesirable weed species it is
often crossed with other wheatgrasses (Agropryon spp.) to create hybrids
for grazing [2,6]. It can be controlled with chemicals such as
glyphosate, dichlobenil, and fauzifop [50]. Sometimes, however,
chemicals are not effective. In Wisconsin, 2,4-D applied to quackgrass
caused a slight increase in quackgrass cover and no effect on stem
density [23]. In Midwestern prairies, mowing and raking significantly
reduced quackgrass biomass and prevented flowering the following growing
season [13]. Mowing, burning, and chemical application combined may be
the best way to eradicate quackgrass [33].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS

SPECIES: Elymus repens
GENERAL BOTANICAL CHARACTERISTICS :
Quackgrass is a cool-season, exotic, perennial, rhizomatous graminoid.
Its stems are erect, decumbent, and may reach heights of 1 to 3 feet
(0.3-1 m) but more commonly grow to 0.25 to 1 inch (0.5-2 cm) high
[18,21]. Quackgrass is green to whitish, with hirsute to nonhirsute
leaves and awned or nonawned lemmas [18,26]. Rhizomes can grow 23
inches (60 cm) or more from the main shoot before sending out stems [36]
and grow as deep as 8 inches (20 cm) [26]. Dahlberg [12] described how
to identify seeds of the Agropyron genus to distinguish between
desirable and undesirable species.
RAUNKIAER LIFE FORM :
Chamaephyte
Geophyte
REGENERATION PROCESSES :
Quackgrass propagates mainly by rhizomes but also reproduces by seed.
Seed production, however, is reported to be as low as 25 viable seeds
per plant per season [36]. Studies in Alaska showed that seed viability
may vary depending on how deep and long the seeds have been buried;
viablity is reduced significantly after burial for 21 months [10]. In
greenhouse trials, dormancy of seeds buried 6 inches (15 cm) deep was 16
percent, while dormancy of seeds buried 0.8 inch (2 cm) deep was only 5
percent [9]. Cross-pollination is necessary for seed production [44].
Dormancy in rhizome buds has been related to nitrogen deficiencies,
which peak in June [8]. Sod mats can be as dense as 367 meters of
rhizomes per square meter [36].
SITE CHARACTERISTICS :
Quackgrass invades gardens, yards, crop fields, roadsides, ditches, and
just about any disturbed, moist area [21]. It invades mixed-grass
prairies as well as oak (Quercus spp.)-hickory (Carya spp.) and
whitebark pine (Pinus albicaulis) forests [1,24,49]. It can tolerate
some saline conditions in the low-lying valleys of Utah [26].
Salt-tolerant cultivars have been developed by crossing quackgrass with
bluebunch wheatgrass [42]. Elevational range in four western states
follows [14]:
State Elevation
Utah 5,100-8,200 feet (1,554-2,499 m)
Colorado 4,800-10,000 feet (1,463-3,048 m)
Wyoming 4,500-8,000 feet (1,372-2,438 m)
Montana 5,000-6,600 feet (1,524-2,012 m)
Some associate species of quackgrass include sedge (Carex spp.), bulrush
(Scirpus spp.), rush (Juncus spp.), bluebunch wheatgrass, crested
wheatgrass, red top (Agrostis alba), indiangrass (Sorghastrum nutans),
bluestems (Andropogon spp., Schizachyrium spp.), smooth brome (Bromus
inermis), poverty oatgrass (Danthonia spicata), panic grass (Panicum
spp.), Kentucky bluegrass (Poa pratensis), common ragweed (Ambrosia
artemisiifolia), prairie pepperweed (Lepidium densiflorum), prairie
dropseed (Sporobolus heterolepis), Canada thistle (Cirsium arvense),
Carolina geranium (Geranium carolinianum), and bracken fern (Pteridium
aquilinum) [1,5,11,15,24,26,28].
SUCCESSIONAL STATUS :
Quackgrass is an early seral dominant in disturbed areas [15,22,27].
SEASONAL DEVELOPMENT :
Quackgrass flowers from June through August in Colorado, Wyoming, and
Montana; and from June through July in North Dakota [14].
Optimum temperatures for growth are between 68 and 77 degrees Fahrenheit
(20 and 25 deg C), with no growth occurring above 95 degrees Fahrenheit
(35 deg C) or below 35 degrees Fahrenheit (2 deg C) [16,36]. Primary
rhizome growth begins in late May or early June and then again in
September and October [36]. Rhizome growth seems to be favored by low
temperatures [50 deg F(10 deg C)] and long days (18 hours) [36].

FIRE ECOLOGY

FIRE EFFECTS

SPECIES: Elymus repens
IMMEDIATE FIRE EFFECT ON PLANT :
Late spring fires generally reduce quackgrass cover, flowering and
biomass, while early spring fires can increase these.
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
A May burn in oak savannas of Wisconsin significantly reduced quackgrass
and halted flowering [13]. Similar results (reduction in biomass and
cover) have been shown for other areas [23,28]. Burning quackgrass on a
biennial schedule for several years has been effective in eradicating
this species [1,3].
PLANT RESPONSE TO FIRE :
Quackgrass cover can increase following fire.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
Five annual late April to early May burns in Minnesota resulted in a
decrease in quackgrass height but an increase in cover [5]. Plant vigor
was reduced and flowering stopped, but quackgrass continued to spread
into adjacent areas. At the time of the April burns, plant height was
between 3.9 and 5.9 inches (10-15 cm), and during the May burn, heights
were between 5.9 and 9.8 inches (15-25 cm). May and June burns on North
Dakota grasslands "harmed" quackgrass in the first postburn season, but
quackgrass recovered to almost preburn levels by the second postburn
season. Following the late June fire, quackgrass showed a slight
increase in cover, height, shoot density, production, and flowering
[39]. Wisconsin grassland fires in March caused an increase in seed
production by July and August [23].
The Research Project Summary, Herbaceous responses to seasonal burning in
experimental tallgrass prairie plots provides information on postfire response
of quackgrass in experimental prairie plots that was not available when this
species review was originally written.
FIRE MANAGEMENT CONSIDERATIONS :
Cool-season grasses such quackgrass are best eliminated with early
spring burns [20,31,34]. Cool-season grasses can grow in the fall
following summer dormancy; therefore, fall burns might also help reduce
undesirable cool-season grasses [41].